Safety device for a pre-filled syringe and an injection device

A safety device for a pre-filled syringe comprising

• a support body adapted to mount the pre-filled syringe,
• a first needle shield slidably arranged with respect to the support body and
• a second needle shield slidably arranged with respect to the support body and releasably retained in a retracted position (PR),
• wherein a proximal movement of the first needle shield with respect to the support body releases the retention of the second needle shield in the retracted position (PR), characterised in that the second needle shield comprises a helical recess accommodating a projection of the support body so that it is allowed to slide parallel to a central axis (A) of the safety device in the distal direction towards an advanced position (PA) wherein it is forced to rotate with respect to the support body.